The demands on automobiles for better fuel economy have been increasing in recent years as concern with environmental issues has been rising, and good fuel economy is also being required of the rubber compositions used for automotive tires. For example, rubber compositions containing a conjugated diene polymer (e.g., polybutadiene, butadiene-styrene copolymer, and so forth) and a filler (e.g., carbon black, silica, and so forth) are used for the rubber compositions for automotive tires.
An example of a method for improving the fuel economy is provided in Patent Document 1; this method uses a diene rubber that has been modified by an organosilicon compound that contains an amino group and alkoxy group. However, there has been demand in recent years for additional improvements in fuel economy. Wet-grip performance and abrasion resistance are also properties required of the rubber compositions used for automotive tires; however, these properties generally assume an inverse relationship with the fuel economy and it has been difficult to obtain these individual properties in good balance at high property levels.
Patent Document 1: JP 2000-344955 A